Generally, conventional automatic transmissions include a torque converter to transfer engine torque from an engine to an input of a main gearset that includes a plurality of interconnected planetary gearsets. A plurality of fluid-pressure-operated drive of brake clutches and/or brake bands (collectively “engagement elements”) are typically connected to the individual elements of the planetary gearsets and are applied or released in various combinations to thereby select a desired transmission gear ratio. At least one freewheeling or overrunning clutch often operates the clutches and/or brake bands to “shift” the transmission from one selected transmission gear ratio to another selected transmission gear ratio.
In operation, such conventional automatic transmission ate sequentially shifted up and down by the controller through the several available transmission gear ratios by initiating “single swap” events characterized by releasing one applied drive or brake clutch and applying another idle clutch. Preferably, the controller can shift the transmission up and down “through the gears” in such a manner that the vehicle's operator does not notice or feel the gear shifts, by each time applying and releasing a single pair of clutches.
Unfortunately, by relying exclusively on “single swap” up-and down-shifting, such conventional transmission suffer from the disadvantage of not being able to use some of the gear ratios that might be available if several drive or brake clutches and/or brake bands were applied and/or released during the shifting event, thereby also limiting the drivability, performance, and fuel economy of the vehicle's powertrain.